William c



( No Model.)

W! n SAFETY VENT PUB STEAM BOILERS.

No. 372,289. Patented N0v.z1, 1-887.

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UNITED STATES PATENT Grams.

WILLIAM (IBAKER, OF NEW YORK, N. Y., ASSIGNOR TO THE BAKER HEATERCOMPANY, OF SAME PLACE.

SAFETY-VENT FOR STEAM-BQILERS.

SPECIFICATION forming part of Letters Patent No. 372,289, dated November1, 1887.

Application filed February 12, 1886. Serial No. 101,714. (No model) ToaZZ whom it may concern.-

Be it known that I, WILLIAM C. BAKER, of the city and State of New York,have invented an Improvement in Safety-Vents for Steam- Boilers, 800.,of which the following is a specification.

In the use of safety-valves there is danger in consequence of theuncertainty of the action. The valve is liable to adhere to the seat inconsequence of oxidation and the presence of foreign matter, orotherwise. Besides this, the valve may be fastened down or over- Platesof metal have been secured by rings to cases in which the steam isallowed to act; but the pressure required for opening the vent willoften depend upon the force with which the metal plate is bolted andheld by" the clampingrings. Where fusible alloy is employed, the samemay be exposed to the action of currents of air or'other chillinginfluonce that keep the metal at a less temperature than they steam, andthe fusing-point is sometimes changed during the lapse of time.

My present invention is especially adapted to the heating apparatus madeuse of in railway-cars, where danger arises from careless ness on thepart of the porter or other attendant. In the heating apparatus ofrailway-cars it has been usual to place an expansion vessel above theroof of the car and to connect the safety-valve with the same. In thisposition the safety-valve is not easily accessible, and it is liable tobecome obstructed, and it is seldom examined to ascertain whether it isin proper condition.

My improvement relates to a safety-vent made of a metallic case,preferably of castiron, connected by a tube to the boiler. heatingapparatus, or other generator that is to be protected from explosion;and this safety-vent is in the form of a hollow bulb, the lower portionof which is sufficiently heavy and strong to be firmly attached to thevent-pipe, and the upper part is reduced in thickness, so as to beconsiderably weaker than any other portion of the apparatus with whichit is connected, thereby allowing for the upper portion of the vent-bulbbeing broken away and blown off by an excessot' pressure, so that thesteam or other fluid is allowed to issue freely through I generator.

the vent-pipe and reduce the pressure in the The exterior of thissafety-vent, beingsmooth, can beplated, coated, or painted, so as toprotect it from atmospheric influences, and it is of very triflingexpense to manufacture; and in case of over-pressure the breaking andthe immediate reduction of the pressure is absolutely certain, and theremoval of the broken safety-vent and the substitution of anew oneoccupies but a few moments, and can be done either by hand or by awrench.

In the drawings, Figure l is a vertical section of the safety-vent and aportion of the tube leading to the boiler or other generator, and Fig. 2is an inverted plan of the same.

The safety-vent is preferably a hollow flattened spheroid, and the lowerside, A, of the same and the circular sides B are of sufficiently thickmaterial to correspondin strength with the pipes and other parts madeuse of in the heating or other apparatus; but the top 0 of thesafety-vent is considerably reduced in thickness, so that its strengthis diminished to any desired extent. I prefer to mount this bulb inalathe and turn off the interior surface ofthe top or diaphragm G with asuitable tool, and then to true oft the exterior surface of the disk ortop and reduce the thickness to whatever extent is necessary, so thatthe breakingpoint of the disk portion ofthe safety-vent may correspondwith the desired maximum pressure. This is readily determined bymeasuring the thickness of the disk portion and subjecting the-vent-bulbto the action of hydraulic or other pressure until the disk is torn openor blown off. Safety-vents having a corresponding thickness will alwaysbe sufficiently reliable for use with the given pressure towhich theyare adapted, because, in case of imperfection in the metal, the worstresult that can J happen will be the breaking of the safety-vent at'aless pressure than that intended.

In order to give access for turning oft the inner surface of the diskportion, it is preferable to make use of a large opening in the base orbottom of the safety-vent and to screwthread the metal and introduce areducingnut, E, between the bottom portion, A, of the safety-vent andthe tube F, leading to the boiler or other apparatus.

IOO

Usually it is preferable to make use of a safety-vent the exteriorsurface of which is plain or smooth, so that the bulb can be grasped andunscrewed or replaced by hand without the use ofa wrench; but theredueingnut E should have a square surface, upon which a wrench can beapplied for screwing the same upon a pipe or unscrewing it, whennecessary.

lhe shape of this safety-vent may vary and be either circular orpolygonal, and it may be in the form of a ring, with the edgessufficiently thick to allow for attachment to the place where the steam,compressed air, or other fluid will act upon one side. The size andthickness of this safety-vent may be varied according to the capacity ofthe boiler or other generator and the pressure that it is exposed to.

I claim as my invention 1. A hollow safety-bulb formed ofonc piece ofmetal, with a thick strong portion to which the pipe leading to thegenerator or source of pressure is connected and a thinner portion theouter and inner surfaces of which are turned off or trued to render themetal of uniform thickness where the rupture is to take place underexcessive pressure, substantially as set forth.

2. A hollow safety-bulb formed of one piece of metal, with a thickstrong portion to which the pipe leading to the source of pressure isconnected and a thinner portion, to break away by excessive pressure,both surfaces of which thinner portion are turned off or trued to renderthe metal of uniform thickness where the rupture is to take place, thethickened portion having a screw-thread for the pipeeonnection and alarge opening to give access for turning off the inner surface,substantially as set forth.

3. The combination, with the pipe connect ing to the source of pressureand the nut E thereon, of the hollow safety-bulb screwed upon the nutand having a thick strong edge and a thinner portion the outer and innersue faces of which are turned off or trued to render the metal ofuniformthickness where the rupture from excessive pressure is to take place,substantially as set forth.

Signed by me this 9th day of February, v A. D. 1886.

\V. O. BAKER.

Witnesses:

GEO. T. PINOKNEY, \VALLAcE L. SERRELL.

